A Trio of Revelations: Weakly Solvating Modulation in Aqueous Electrolytes for Zinc Metal Batteries

Abstract

The emerging concept of weakly solvating electrolytes in multivalent ion aqueous batteries has garnered attention due to their enhanced kinetic performance at a low cost. This article aims to dissect the concept of "weakly solvating electrolyte" into three revelations, i.e., ion solvation, hydrogen bonding strength, and ionic interactions. It is revealed that a weakly interacting solvent must satisfy the requirements of having a solvation strength weaker than ionic interaction than water molecules, as well as disrupting rather than strengthening hydrogen bonding within them. Moreover, electrolyte chemistry requires balancing multiple factors, and the same weakly interacting solvent exhibits varying effects with the variation of the anions of zinc salts. This study offers quantitative descriptors to the concept of weak solvation, particularly for aqueous electrolytes, and provides insights for future electrolyte advancements for multivalent ion batteries.